Playback activity monitoring: API for format and spatialization

Add SystemApi to query sample rate, channel mask and spatialization
status from AudioPlaybackConfiguration, information coming from
AudioFlinger.
Fix synchronization on updateable properties (use a lock instead
of this).

Bug: 263300713
Test: atest android.media.audio.cts.AudioPlaybackConfigurationTest
Change-Id: Iad94f0b25ea89efbfb4db047c68cc98b47e85c86